Various devices have been developed and used for applying a drawing or pulling force to portions of the body, usually using weights. The application of such force, referred to as traction, is variously used as a corrective or therapeutic measure, and is also used in fracture cases to keep the end of bone at the fracture point in the desired place. Traction can take several forms including skeletal and skin traction in which the force is applied through pins, wires, tape or other fasteners placed on or through the body part. In head traction, pull is exerted on the head to relieve pressure and deformity in cases of neck injury.
In a hospital environment it is very important to be able to apply force at a specific desired angle, and the force must be adjustable over a rather wide range. Furthermore, the device used to apply the traction must be attachable to a variety of patient support structures including operating tables, patient conveying tables such as stretcher beds, and hospital beds; and must be quiet strong.
Traction devices for weight traction are all broadly similar in that they constitute structures for supporting the rotation axis of a pulley over which a rope or cord is passed between the selected portion of the patient's body and a weight with the weight hanging relatively freely. Examples of prior art devices are found in the following U.S. Patents:
U.S. Pat. No. 3,856,003; Pfluger PA0 U.S. Pat. No. 3,826,490; Mossman PA0 U.S. Pat. No. 3,086,519; Pari PA0 U.S. Pat. No. 3,063,445; Ries PA0 U.S. Pat. No. 2,638,091; Varco PA0 U.S. Pat. No. 2,550,983; Ettinger PA0 U.S. Pat. No. 2,186,036; Peachey
While each of these devices appears to be usable in a specific set of circumstances, none meets the requirements of strength, adaptability to a variety of support bodies and a wide range of angles over which traction force can be applied.